Studies on the syntheses of heterocyclic compounds. Part CCCXV. Modified total synthesis of (±)-galanthamine through phenol oxidation

Abstract

Oxidation of 2-bromo-5-hydroxy-N-(4-hydroxyphenethyl)-4-methoxy-N-methylbenzamide (VIII) with ferricyanide afforded the narwedine-type enone (X) in an excellent yield (40%). Reduction of (X) with lithium aluminium hydride gave (±)-galanthamine (II) and (±)-epigalanthamine (XXI) in yields of 50 and 40% respectively. Oxidation of (II) with manganese dioxide afforded (±)-narwedine (XIX) This work also constitutes a formal synthesis of (±)-lycoramine.